Multi-level parking systems for automobiles, trucks, etc., have been used for many years. In many locations, single level parking is not cost effective. The most cost effective multi-level parking systems employ parking platforms that move vertically from the loading/unloading area to storage areas located above to save footprint space. Two level parking systems are used where height restrictions are in effect but in areas where there are no height restrictions three or more level systems are utilized.
When multi-level parking systems with three or more levels are used, they are usually built with platforms that stack on top of each other at the lowest level. When the platforms of the prior art are stacked in the lower-most position, the cumulative thickness of the stacked platforms presents an obstacle to driving a vehicle both on and off the top-most platform. The increased height of the stacked platforms prevents vehicles lacking sufficient ground clearance from being driven on or off the platforms. Various types of ramp systems have been used, which include ramps that are progressively longer as the stack incorporates additional levels.
In the more modern equipment, the platforms are designed to nest together at the lower positions. This reduces the height of the platform stack, which allows the vehicles to be driven on and off more easily. With that design, the rise and fall of the ramp is used as a structural cross member to stiffen the platform laterally. A consequence is that, when lowered, each platform and its associated ramp must lie on top on the platform below. For example, see U.S. Pat. No. 4,674,938 for a vertical parking system.
The problem with this platform nesting and stacking system is that the ramps must have a gradual rise and fall so the vehicles can be driven on and off the platforms easily. When the ramps are made with more gradual inclines for easier loading and unloading, the construction is typically thicker to maintain the required section laterally across the platform. Because each platform must have a ramp to maintain lateral strength this increase in ramp thickness creates a heavier and more costly set of platforms. Therefore, there is a need for a lightweight, sufficiently strong drive-on ramp system.